Well the same thing happened 2 my Brother in-law. He had a Original PS3 the 1st day of Release here in the U.S. He payed almost $800 for the damn thing, NE Ways, It YLOD'd him 3 days B4 Christmas last year.
So i talked him in 2 Buying a 250GB Slim, & he Did. So i brought my PS3 Slim over 2 his house and i Swapped out my HDD & put his “OLD” HDD in2 my Slim, connected a “5e Patch” ethernet cable 2 his “NEW” 250GB PS3 Slim.
Fired both systems up, after he set up all his settings we transfered all the contents of his “Original” HDD on MY PS3 Slim 2 HIS “NEW SLIM” Using the “DATA TRANSFER UTILITY” under “SYSTEM SETTINGS”…….. It took Appox 50mins 2 complete.
Hope this helps, Because it help my Brother In-Law & now he is Complete Again.